[llvm-exegesis] Ignore double spaced separators in asm strings
[llvm-exegesis] Ignore double spaced separators in asm strings

Some asm has double spaces between operands, the deserializer was keeping these empty split pieces, causing assertions later on:

'ADC16mi RDI i_0x1x  i_0x0x  i_0x1x'

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@341799 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm