RFR(S): 8234791: Fix Client VM build for x86_64 and AArch64

[Pengfei Li (Arm Technology China)]

Hi,

Please help review this small fix for 64-bit client build.

Webrev: http://cr.openjdk.java.net/~pli/rfr/8234791/webrev.00/
JBS: https://bugs.openjdk.java.net/browse/JDK-8234791

Current 64-bit client VM build fails because errors occurred in dumping
the CDS archive. In JDK 12, we enabled "Default CDS Archives"[1] which
runs "java -Xshare:dump" after linking the JDK image. But for Client VM
build on 64-bit platforms, the ergonomic flag UseCompressedOops is not
set.[2] This leads to VM exits in checking the flags for dumping the
shared archive.[3]

This change removes the "#if defined" macro to make shared archive dump
successful in 64-bit client build. By tracking the history of the macro,
I found it is initially added as "#ifndef COMPILER1"[4] 10 years ago
when C1 did not have a good support of compressed oops and modified to
current shape[5] in the implementation of tiered compilation. It should
be safe to be removed today.

This patch also fixes another client build issue on AArch64.

[1] http://openjdk.java.net/jeps/341
[2] http://hg.openjdk.java.net/jdk/jdk/file/981a55672786/src/hotspot/share/runtime/arguments.cpp#l1694
[3] http://hg.openjdk.java.net/jdk/jdk/file/981a55672786/src/hotspot/share/runtime/arguments.cpp#l3551
[4] http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/323bd24c6520#l11.7
[5] http://hg.openjdk.java.net/jdk8/jdk8/hotspot/rev/d5d065957597#l86.56

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Thanks,
Pengfei