RFR: JDK-8300531: Update MSVC optimization flags to match GCC/Clang [v10]

[Justin King]

> Update MSVC CFlags to be more consistent with other compilers. Also disables RTTI in a simliar manner to GCC/Clang for the JVM.

Justin King has updated the pull request incrementally with one additional commit since the last revision:

  Add comments clarifying -Oy-
  
  Signed-off-by: Justin King <jcking at google.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12073/files
  - new: https://git.openjdk.org/jdk/pull/12073/files/53a2ef3a..af74073c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12073&range=09
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12073&range=08-09

  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12073.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12073/head:pull/12073

PR: https://git.openjdk.org/jdk/pull/12073