[foreign-memaccess+abi] RFR: Remove printf and vprintf tests [v2]

[Jorn Vernee]

> This patch removes the printf and vprintf tests, since the symbols are not available on Windows in the UCRT.
> 
> gmtime is similarly an inline function that maps to something else, but in that case there is a drop-in replacement symbol name _gmtime64 we can call instead.
> 
> This fixes the missing symbol errors in StdLibTest.

Jorn Vernee has updated the pull request incrementally with two additional commits since the last revision:

 - Rather than removing or disabling tests on Windows, fall back to a helper library that can return the right function addresses to us.
 - Only disable tests on Windows instead.

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/536/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/536/files/3c741cf7..7b7dde2b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=536&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=536&range=00-01

  Stats: 206 lines in 2 files changed: 198 ins; 1 del; 7 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/536.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/536/head:pull/536

PR: https://git.openjdk.java.net/panama-foreign/pull/536