RFR: 8247522: assert(is_aligned(class_space_rs.base(), class_space_alignment)) failed: Sanity

[jiefu(傅杰)]

Hi all,

JBS:    https://bugs.openjdk.java.net/browse/JDK-8247522
Webrev: http://cr.openjdk.java.net/~jiefu/8247522/webrev.00/

This bug was triggered after JDK-8245707.
The reason is that ccs_begin_offset[1] is incorrect when archive_space_alignment != class_space_alignment.

Before JDK-8245707, archive_space_alignment = class_space_alignment = 4k.
After JDK-8245707,  archive_space_alignment = 4k, class_space_alignment = 16k.

When the assert happened, we had observed base_address[2] = 4096, which is unaligned to class_space_alignment=16k.

- Testing:
         tier1 on Linux/x64

Thanks a lot.
Best regards,
Jie

[1] http://hg.openjdk.java.net/jdk/jdk15/file/1c81917f228b/src/hotspot/share/memory/metaspaceShared.cpp#l2505
[2] http://hg.openjdk.java.net/jdk/jdk15/file/1c81917f228b/src/hotspot/share/memory/metaspaceShared.cpp#l2514