factored out retrieving the host architecture name to handle variations in value of os.arch system property
removed more uses of HotSpotGraalRuntime.getHostProviders() (GRAAL-363)
replaced HotSpotGraalRuntime.wordKind with an access via the host backend (GRAAL-363)
removed yet more uses of HotSpotGraalRuntime.getHostProviders() (GRAAL-363)
preliminary support for initializing multiple ForeignCallProviders and LoweringProviders (GRAAL-363)

--HG--
rename : graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotLoweringProvider.java => graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/meta/HotSpotHostLoweringProvider.java
prevent npe in Buffer.copyData() when Buffer.data is null
replace new InternalError("NYI") with GraalInternalError.unimplemented()
gave HSAIL its own Replacements implementation (HSAILHotSpotReplacementsImpl)
marked HSAIL tests that rely on unimplemented features
fixed regression
added support disassembling during CodeGen