Fix GenerationalHeapParser

[loyispa]

Hello, i found that GenerationalHeapParser couldn't parse following CMS concurrent-mode-failure logs:

case1:

83.371: [CMS-concurrent-abortable-preclean-start]
83.751: [GC 83.751: [ParNew: 17024K->17024K(19136K), 0.0000236 secs]83.751: [CMS83.751: [CMS-concurrent-abortable-preclean: 0.026/0.380 secs] [Times: user=0.41 sys=0.04, real=0.38 secs] 
 (concurrent mode failure): 103355K->96073K(107776K), 0.5668205 secs] 120379K->96073K(126912K), [CMS Perm : 15591K->15585K(28412K)], 0.5669586 secs] [Times: user=0.57 sys=0.00, real=0.57 secs] 

case2:

2024-02-23T16:14:07.550+0800: 15897423.337: [GC (CMS Initial Mark) [1 CMS-initial-mark: 1398143K(1398144K)] 1957374K(1957376K), 0.4527312 secs] [Times: user=0.57 sys=0.00, real=0.45 secs]
2024-02-23T16:14:08.003+0800: 15897423.790: [CMS-concurrent-mark-start]
2024-02-23T16:14:08.172+0800: 15897423.959: [Full GC (Allocation Failure) 2024-02-23T16:14:08.172+0800: 15897423.959: [CMS2024-02-23T16:14:10.825+0800: 15897426.612: [CMS-concurrent-mark: 2.820/2.822 secs] [Times: user=2.57 sys=0.00, real=2.82 secs]
 (concurrent mode failure): 1398144K->1398143K(1398144K), 8.7753717 secs] 1957375K->1957374K(1957376K), [Metaspace: 63759K->63759K(1107968K)], 8.7755118 secs] [Times: user=8.17 sys=0.00, real=8.78 secs]

In these cases, there will be an extra SPACE before (concurrent mode failure), so CONCURRENT_MODE_FAILURE_DETAILS and CONCURRENT_MODE_FAILURE_DETAILS_META failed to recognize them. Please take a look :)

[loyispa]

@kcpeppe do you have time to take a look? It's very easy to verify this issue.