RFR: 8278037: Clean up PPC32 related code in C1 [v2]

[Ao Qi]

> `_tmp1` and `_tmp2` were [removed](https://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/faaed259df37#l13.173) in [JDK-8160245](https://bugs.openjdk.java.net/browse/JDK-8160245), but they are still used.
> 
> This should cause a build error. I don't have a ppc32 machine for the test. It's also not found at https://builds.shipilev.net. Is ppc32 a supported compiler1 platform?

Ao Qi has updated the pull request incrementally with one additional commit since the last revision:

  8278037: Removed PPC32 C1

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6625/files
  - new: https://git.openjdk.java.net/jdk/pull/6625/files/90f402a6..27c3dc91

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6625&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6625&range=00-01

  Stats: 57 lines in 3 files changed: 0 ins; 53 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6625.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6625/head:pull/6625

PR: https://git.openjdk.java.net/jdk/pull/6625