RFR: 8359386: Fix incorrect value for max_size of C2CodeStub when APX is used

[Srinivas Vamsi Parasa]

The goal of this PR is to fix the value of max_size of the C2CodeStub hardcoded in the C2_MacroAssembler::convertF2I() function when Intel APX instrucitons are used. Currently, max_size is hardcoded to 23 (introduced in [JDK-8306706](https://bugs.openjdk.org/browse/JDK-8306706)) . However, this value is incorrect when Intel APX instructions with extended general-purpose registers (EGPRs) are used in the code stub as using EGPRs with APX instructions leads to an increase in the instruction encoding size by additional 4 bytes.

Without this fix, we see the following errors for the C2 compiler tests below:

compiler/vectorization/runner/ArrayTypeConvertTest.java
compiler/intrinsics/zip/TestFpRegsABI.java




# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/src/hotspot/share/opto/c2_CodeStubs.cpp:50), pid=3961123, tid=3961332
# assert(max_size >= actual_size) failed: Expected stub size (23) must be larger than or equal to actual stub size (24)
#
# JRE version: OpenJDK Runtime Environment (26.0) (fastdebug build 26-internal-adhoc.parasa.jdkdemotion)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 26-internal-adhoc.parasa.jdkdemotion, mixed mode, sharing, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x955a77] C2CodeStubList::emit(C2_MacroAssembler&)+0x227
#


This PR fixes the errors in the above-mentioned tests.

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

Commit messages:
 - 8359386: Fix incorrect value for max_size of C2CodeStub when APX is used

Changes: https://git.openjdk.org/jdk/pull/25787/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25787&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359386
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25787.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25787/head:pull/25787

PR: https://git.openjdk.org/jdk/pull/25787