RFR: 8287373: remove unnecessary paddings in generated code

[Boris Ulasevich]

The goal is to remove unnecessary paddings in generated code. The alignment of the [Stub Code] section is determined by the same value as the alignment of the [Entry Point] section: the CodeEntryAlignment parameter with default values 64B on AARCH, and 32B on AMD.

Large entry alignment values are questionable for entry section. For example, Arm Neoverse N1 Software Optimization Guide recommends to align subroutines to 32B, while static compilers uses an even smaller value of 16B. However, with this change, I suggest to apply different (and smaller) values for [Constants] and [Stub Code] section alignments. This makes overall code 2% smaller on AARCH.

The correctness of the changes is checked by jtreg. Performance tested by Renaissance and SpecJBB benchmarkds on AARCH and AMD.

Example. Dummy method disassembly on AARCH, before vs after:

[Verified Entry Point]                          |  [Verified Entry Point]
  78c63b80:   nop                               |    7437e480:   nop
  78c63b84:   sub     x9, sp, #0x20, lsl #12    |    7437e484:   sub     x9, sp, #0x20, lsl #12
  78c63b88:   str     xzr, [x9]                 |    7437e488:   str     xzr, [x9]
  78c63b8c:   sub     sp, sp, #0x20             |    7437e48c:   sub     sp, sp, #0x20
  78c63b90:   stp     x29, x30, [sp, #16]       |    7437e490:   stp     x29, x30, [sp, #16]
  78c63b94:   orr     w1, wzr, #0x10            |    7437e494:   orr     w1, wzr, #0x10
  78c63b98:   bl      78343e00                  |    7437e498:   bl      73a61980
  78c63b9c:   .inst   0x00000000 ; undefined    |    7437e49c:   .inst   0x00000000 ; undefined
  78c63ba0:   .inst   0x00000000 ; undefined    |
  78c63ba4:   .inst   0x00000000 ; undefined    |
  78c63ba8:   .inst   0x00000000 ; undefined    |
  78c63bac:   .inst   0x00000000 ; undefined    |
  78c63bb0:   .inst   0x00000000 ; undefined    |
  78c63bb4:   .inst   0x00000000 ; undefined    |
  78c63bb8:   .inst   0x00000000 ; undefined    |
  78c63bbc:   .inst   0x00000000 ; undefined    |
[Stub Code]                                     |  [Stub Code]
  78c63bc0:   ldr     x8, 78c63bc8              |    7437e4a0:   ldr     x8, 7437e4a8
  78c63bc4:   br      x8                        |    7437e4a4:   br      x8
  78c63bc8:   .inst   0x78343e00 ; undefined    |    7437e4a8:   .inst   0x73a61980 ; undefined
  78c63bcc:   .inst    ; undefined              |    7437e4ac:   .inst    ; undefined
[Exception Handler]                             |  [Exception Handler]
  78c63bd0:   b       783ee080                  |    7437e4b0:   b       73b0c100
[Deopt Handler Code]                            |  [Deopt Handler Code]
  78c63bd4:   adr     x30, 78c63bd4             |    7437e4b4:   adr     x30, 7437e4b4
  78c63bd8:   b       78343ac0                  |    7437e4b8:   b       73a61620
  78c63bdc:   .inst   0x00000000 ; undefined    |    7437e4bc:   .inst   0x00000000 ; undefined

-------------

Commit messages:
 - fixing the CodeBuffer overflow assert on x86 build: SharedRuntime::generate_handler_blob asks a 1KB buffer,
 - rollback InteriorEntryAlignment change
 - jtreg/compiler tests update
 - Undo CodeEntryAlignment modification. Each code section (constants,code,stubs) have got its own alignment
 - use InteriorEntryAlignment for code sections

Changes: https://git.openjdk.java.net/jdk/pull/8453/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8453&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8287373
  Stats: 60 lines in 9 files changed: 28 ins; 3 del; 29 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8453.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8453/head:pull/8453

PR: https://git.openjdk.java.net/jdk/pull/8453