Multi-line regular expression where no match exist for pattern part after long catch-all matches from start of match until end of file

[vgriph]

Description of the Issue

Doing a find using a regular expression with ". matches newline" enabled using a regular expression similar to:

(Start:).*^(\1 End pattern) 

where a match for (Start:) exists, but no match for ^(\1 End pattern) over a large file will match from (Start:) to the end of the file.

Steps to Reproduce the Issue

1. Create a new text file with the following content:
   On a text file with contents similar to:

1>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P1)
1>FastUpToDate: ...
1>FastUpToDate: Project is up to date. (P1)
1>FastUpToDate: Up to date check completed in 10 ms (P2)
2>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P2)
2>FastUpToDate: ...
2>FastUpToDate: Input marker is newer than output marker, not up to date. (P2)
2>FastUpToDate: Up to date check completed in 49,1 ms (P2)
3>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P3)
3>FastUpToDate: ...
3>FastUpToDate: Project is up to date. (P3)
3>FastUpToDate: Up to date check completed in 14 ms (P3)

(or use npp-regex-bug.txt)

2. Duplicate the line 2>FastUpToDate: ... so that it appears at least 2093 times in the file.
3. Go to the start of the file and search for (\d+>FastUpToDate:).*^(\1 Project is up to date\.) using the "Regular expressions" and ". matches newline" options.
4. Click "find next"

Expected Behavior

First hit is the lines

1>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P1)
1>FastUpToDate: ...
1>FastUpToDate: Project is up to date. 

Second hit is the lines

3>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P3)
3>FastUpToDate: ...
3>FastUpToDate: Project is up to date. 

Actual Behavior

First hit were the lines

1>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P1)
1>FastUpToDate: ...
1>FastUpToDate: Project is up to date. 

Second hit was from the line 2>FastUpToDate: Adding UpToDateCheckBuilt outputs: (P2) to the end of the file.

Debug Information

Notepad++ v7.8.7 (64-bit)
Build time : Jun 5 2020 - 02:38:56
Path : C:\Program Files\Notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 1803
OS Build : 17134.1553
Current ANSI codepage : 1252
Plugins : DSpellCheck.dll mimeTools.dll NppConverter.dll NppExport.dll XMLTools.dll

[sasumner]

Very likely another manifestation of #4761 -- catastrophic regex engine failure -- that is currently not detected and handled well in Notepad++.