RFR: 8281440: AWT: Conversion from string literal loses const qualifier

[Daniel Jeliński]

This patch fixes AWT compilation under VisualStudio 2019 with `/Zc:strictStrings` enabled.

Strict string handling is already enabled in GCC and Clang. With some effort we should be able to enable it in MSVC as well.

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Commit messages:
 - Compile with strict string handling

Changes: https://git.openjdk.java.net/jdk/pull/7379/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7379&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281440
  Stats: 22 lines in 10 files changed: 0 ins; 0 del; 22 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7379.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7379/head:pull/7379

PR: https://git.openjdk.java.net/jdk/pull/7379