RFR: 8337396: Cleanup usage of ExternalAddess

[Vladimir Kozlov]

`ExternalAddess` should be used only for data load. For calls (and jump) instructions we should use `RuntimeAddress` which uses `runtime_call_Relocation`.

I found few places where `ExternalAddess` is used incorrectly and fixed them.

I also added code to print "hottest" (most referenced) `ExternalAddess` addresses in global table to move them into static global tables which will be introduced by [JDK-8334691](https://bugs.openjdk.org/browse/JDK-8334691) and [JDK-8337519](https://bugs.openjdk.org/browse/JDK-8337519).

Here is current output from debug VM on MacBook M1 (Aarch64):

External addresses table: 6 entries, 324 accesses
0:      158 0x00000001082de0f0 : extn: vmClasses::_klasses+480
1:       84 0x00000001082ddf20 : extn: vmClasses::_klasses+16
2:       40 0x00000001082c4790 : extn: SharedRuntime::_partial_subtype_ctr
3:       24 0x00000001082bdb04 : extn: JvmtiExport::_should_notify_object_alloc
4:       18 0x0000000118384080 : stub: forward exception


on MacOS-x64:

External addresses table: 143 entries, 44405 accesses
0:    11766 0x00000001047922a0 : extn: CompressedOops::_narrow_oop
1:    11002 0x0000000104474384 : 'should not reach here'
2:     9672 0x0000000104581a90 : extn: ClassLoader::file_name_for_class_name(char const*, int)::class_suffix+882068
3:     2447 0x0000000104508005 : extn: ClassLoader::file_name_for_class_name(char const*, int)::class_suffix+383753
4:     1916 0x000000010458188e : extn: ClassLoader::file_name_for_class_name(char const*, int)::class_suffix+881554


and on linux-x64:

External addresses table: 143 entries, 77297 accesses
0:    22334 0x00007f35d5b9c000 : ''
1:    19789 0x00007f35d55eea1f : 'should not reach here'
2:    18366 0x00007f35d5747bb8 : 'MacroAssembler::decode_heap_oop: heap base corrupted?'
3:     5036 0x00007f35d56e4d40 : 'uncommon trap returned which should never happen'
4:     3643 0x00007f35d57479f8 : 'MacroAssembler::encode_heap_oop: heap base corrupted?'


Few points about difference in output:
1. aarch64 does not use `ExternalAddess` or any relocation for messages (strings).
2. `stub: forward exception` corresponds to `StubRoutines::forward_exception_entry()` for which C2 generates tail-call from [C2's stubs](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/generateOptoStub.cpp#L258C48-L258C87). It is difficult to convert it to `RuntimeAddress` because how relocation for constants in C2 are handled.
3. linux-x64 implementation of `dlladdr()`, I used to print C++ symbol name, only works for functions:
    `0x00007f35d5b9c000` points to `CompressedOops::_narrow_oop._base` from code in [MacroAssembler::verify_heapbase()](https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/macroAssembler_x86.cpp#L5760) and on aarch64 [verify_heapbase()](https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp#L2959) is empty (guarded by `#if 0`).
4. I think `ClassLoader::file_name_for_class_name()+...` on MacOSX-x64 corresponds to strings on linux-x64.

Additionally I moved asserts before locks in `ExternalsRecorder` methods.

Tested: tier1-3, xcomp, stress

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

Commit messages:
 - 8337396: Cleanup usage of ExternalAddess

Changes: https://git.openjdk.org/jdk/pull/20412/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20412&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337396
  Stats: 104 lines in 5 files changed: 86 ins; 3 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/20412.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20412/head:pull/20412

PR: https://git.openjdk.org/jdk/pull/20412